Asymmetric Syntheses of S,S-Dialkyl-Substituted Sulfoximines and Related Heterocycles

Enantiomerically enriched forms of a sulfoximine-based myristic acid analogue are prepared using either an asymmetric desymmetrization with a chiral base, or an enantioselective oxidation procedure as key steps. Additionally, a variety of 2-oxa-2-alkyl 3,4-dihydro 2,1-benzothiazines are synthesized via intramolecular metal-catalyzed N-arylation of appropriately functionalized sulfoximines with tethered 2-bromoaryl substituents. In turn, the sulfoximines are prepared by lithiation-alkylation sequences including enantioselective deprotonation steps or the use of an optically active sulfoxide. Using this methodology, the range of accessible 3,4-dihydro 2,1-benzothiazine derivatives is expanded.